This invention pertains to machines for making packages from web material, and deals more particularly with a sealing mechanism for use in such a machine for sealing at least two layers of a body of web material to one another as the web material is moved through the machine.
In package making machines, it is quite common to form seals in web material by two sealing jaws which in a seal making cycle from an open position move to a closed position at which the web material is squeezed therebetween. During the closed state of the jaws, the seal may be formed in various different ways as by applying heat from one or the other or both of the jaws to a heat sealable web material, by applying the pressure of the jaws to a pressure sensitive web material, or by applying clips, staples, bands, adhesive strips or other fasteners to the material. The present invention concerns primarily an apparatus or mechanism for operating such sealing jaws and may be used in various different types of package making machines and for making various different forms of seals. By way of example, the mechanism is shown herein as part of a vertical forming, filling and sealing packaging machine for making package end seals, but it will be understood that the invention in its broader aspects is not limited to this particular application.
The general object of this invention is to provide a sealing mechanism for a web fed package making machine including two sealing jaws cyclicly moved between opened and closed positions which is of a simple, low cost construction requiring few parts and which is adaptable to being made to have a relatively light weight.
In keeping with the foregoing object, another object of the invention is to provide a jaw type sealing mechanism for a package making machine which eliminates the need for toggle mechanisms, levers, cranks and the like commonly used with prior art mechanisms and wherein the opening and closing action of the jaws in a pure linear motion.
Another object of the invention is to provide a sealing mechanism of the foregoing character wherein both of the sealing jaws are movable relative to the base of the associated machine and when closed meet at the center line of the path of movement of the web material through the mechanism so that the web material upon closing of the jaws is not deflected to one side or the other of its normal path.
A still further object of the invention is to provide a sealing mechanism of the foregoing character which may be arranged either as a stationary unit with the web material being fed by other means therethrough or which may be designed as a reciprocating unit for additional use in pulling or aiding in pulling the web material through the machine.
Other objects and advantages of the invention will be apparent from the following description and from the drawings and claims forming a part hereof.